Before a bunch of artists were driven off tumblr due to the overly strict adult policy (the appeals process etc. was too much of a pain) Tumblr was my go-to for a lot of artists in the niches I followed. Through this, I found a ton of communities- fandoms for the characters created by the artists, collective worldbuilding, etc. Also, within niche fandoms I followed I also found artists that produced wonderful works.

There's still an ongoing webcomic (A Tale of Two Rulers) that's a world where Zelda and Gannon choose to marry instead of war on tumblr. It's incredibly awesome and part of what I'm on tumblr for.